Do BCAAs Break Intermittent Fasting?


Intermittent fasting and taking a branched-chain amino acid (BCAA) supplement offer promising benefits for improving body composition. However, it’s confusing to know if doing both at once is helpful or counterproductive. 

Finding time to squeeze in all of your meals and supplements during the shortened intermittent fasting eating window can be challenging. If you’re used to taking BCAAs before or during a workout, you might wonder if you can still take them during a fasted workout. 

Here’s our take on whether BCAAs will break intermittent fasting.  



Benefits of Intermittent Fasting 

Intermittent fasting is a unique eating style because it’s dictated by when you eat, rather than what you eat. In other words, it’s not a diet. There are several different methods for fasting, but the most common is the 16/8 method. Basically, that means a person fasts for 16 hours and eats during an 8-hour period each day. 

The most appealing benefit of intermittent fasting for bodybuilding is that it might help burn fat while preserving muscle. Basically, fasting forces your body to use up all of its glycogen stores. Then, it turns to fat for energy instead. This process may also improve things like inflammation, gut health, insulin resistance, and blood sugar control. 


What Can You Eat and Drink During a Fast? 

Basically, nothing that has caloric value, or triggers an insulin response. That means no food and only water, plain coffee, and tea to drink. 

Some people drink artificially sweetened beverages, but others avoid them because some sweeteners trigger the release of insulin. The benefits of intermittent fasting are based on the idea that fasting causes insulin levels to drop and fat cells can be used for energy. 

Breaking a fast means insulin levels rise and the body stops using fat for energy. 

Technically, consuming amino acids does break your fast. Amino acids combine to become protein, which contains calories that your body has to metabolize. 

However, taking BCAAs prior to a fasted workout may be an acceptable exception. 


BCAAs and intermittent fasting

Benefits of BCAAs During Intermittent Fasting 

The benefits of taking branch chain amino acids during a fasted workout outweigh the downside of technically breaking a fast for most people. 

BCAAs are unique compared to other amino acids because they are metabolized directly in the muscle, instead of in the liver. 

Since taking BCAAs doesn’t give you a ton of amino acids at once, it won’t add up to a large number of calories breaking your fast. Furthermore, BCAAs alone won’t cause a large insulin response.

BCAAs help with muscle fatigue, so you can workout harder and longer to build more muscle. They also help with muscle recovery so your muscle fibers repair themselves more quickly and you don’t have as much downtime between lifting sessions. 


The most appealing benefit of BCAAs during intermittent fasting is it’s potential to help preserve muscle during a fasted workout. Someone who doesn’t workout in a fasted state likely eats a meal before or after to replenish the body with energy to repair broken down muscle. 

However, working out in a fasted state means a person is not eating anything before or after a workout. Therefore, some worry that they may not build as much muscle during a fasted workout. 

Taking BCAAs before, during, and/or after a workout boosts the muscles with energy during a fasted workout, and helps the muscles recover and rebuild more mass.


You could also go a bit broader and take an essential amino acids supplement like Naked EAAS to cover all nine essential aminos instead of only the BCAAs. 

What You Eat After A Fast Matters Too

Just because intermittent fasting isn’t a diet doesn’t mean you should lose focus on the foods you do eat. You can really maximize the results from this eating style combined with your workouts and BCAA supplement if you eat a diet to support your goals. 


carbohydrates after fasting

Be sure to take some time to plan the best way to meet your macronutrient goals during a shortened eating period. If your goal is to put on muscle, your needs may be high and some strategy may be required to get everything your body needs. Although protein is the most important for building muscle, eating enough carbohydrates and healthy fats will also impact your results. 

Not only will this support the leanest tissue growth, but it will also help give you sustained energy for the duration of your fast. It’s likely you will even notice more energy during your workouts. Staying hydrated during a workout is also key to feeling great during a fasted workout. 


The Bottom Line

If you drink a BCAA supplement during a fast, then technically you’re not truly fasting. However, BCAAs won’t disrupt your fast in the same way as eating a meal. Furthermore, the benefits of BCAAs may outweigh the negatives of breaking a fast. 

If you’re looking for a way to improve your endurance and recovery, as well as help preserve muscle mass during a fasted workout, BCAAs might be a good option for you.